Book 1 - City of St. Petersburg

Concrete Caissons
Concrete caissons are reinforced to resist the required vertical
load and the bending moment caused by a lateral load. In this
application, the caisson would act like a large concrete pile. A
hole would be bored to the desired depth and a sacrificial spiral
weld pipe form would be sunk into the hole. The caisson would
be open to the bottom. A reinforcement cage would be lowered
into the pipe form and the form would be filled with concrete.
The spiral weld pipe form would remain in place. The caisson
can be easily combined with a concrete superstructure and the
concrete portion of the caisson is corrosion resistant. An epoxy
coating can be applied to the sacrificial pipe form if desired for
cosmetic reasons. Using pipe as a form has the advantage of
being easy to handle with respect to cutoff and extension to the
desired length during installation. A concrete caisson may be
the best option for the walkway support as concrete is resilient in
coastal environments and is not affected by marine borers.
Pile Caps
Pile caps evenly distribute the concentrated loads from
the superstructure of the Pier to the supporting pile group.
Orienting the caps transverse to the length of the Pier provides
improved lateral stiffness for environmental forces experienced
during hurricane and tropical storm events. A precast concrete
pile cap at the walkway caissons would expedite construction.
An oversized recess in the pile cap would slip over the top of the
caisson and be grouted in place. A formed and pored pile cap at
the roadway piles would be desired over a precast pile cap. The
batter piles at the roadway bents would complicate alignment of
the pile tops with a recess.
MICHAEL MALTZAN ARCHITECTURE, INC. 3 - 87